1826.] M. Berzelius on some Mineral Species. '23 



Article V. 



Observations on some Mineral Species. Extracted from a Letter 

 of M. Berzelius to M. Alexander Brogniart.* 



Stockholm, March 15, 1825. 



My labours during the last winter have been sometimes 

 devoted to mineralogical subjects. [ think I have already- 

 informed you that the mineral so similar to zircon, which 

 M. Tank showed us at Christiania, and in which I found phos- 

 phoric acid by means of the blowpipe, is a phosphate of yttria. 

 We also observed another mineral found in the sienite of Frede- 

 ricwern, black, very brilliant, and formed of small rectangular 

 prisms. I have analyzed it, and found in it oxide of titanium, 

 zirconia, yttria, lime, the protoxides of iron, manganese, and 

 cerium, and traces of the oxide of tin, potash, silica, and 

 magnesia. I have named it Polymignite, from the multiphcity 

 of its elements. The Levyne sent me by Dr. Brewster is abso- 

 lutely nothing more than chabasie, in which a portion of the 

 lime is replaced by soda. The mesola which I analyzed, and 

 named somewhere in Brewster's Journal, is in the same predica- 

 ment ; it is merely a chabasie rich in soda. 



I have analyzed the last portion that I had left of the mineral 

 containing Thorina. I found in it phosphoric acid, united to 

 oxide of cerium and yttria ; and 1 have discovered that this 

 pretended earth is nothing else but a sub-phosphate of yttria. 

 One element, therefore, must be erased from the catalogue. 



I have examined two arseniates of iron, one from Villa- Ricca, 

 in Brasil, the other from Wurfelerz. I find the formula of the 



first ='Fe As + 2 Fe As + 12 Aq. That is to say, it is a 

 neutral arseniate of the protoxide, in which two-thirds of the 

 latter are converted into deutoxide. {C'est-d-dire, que c'est 

 I'arstniate neutre du protoxide, duns lequel deux tiers de celui-ci 

 sont convertis en deutoxide.) The formula of the wurfelerz is 



Fe' As- + 2 Fe^ As® -f- 36 Aq. It is the common sub-arseniate 

 of the protoxide, m which two-thirds of the protoxide are con- 

 verted into deutoxide.]- 



The scorodite of Saxony is not identical with either of these 

 two arseniates. We, therefore, know three different native 

 arseniates of iron. This analytical labour has led me to revise 



* From the Annales des Sciences Naturelles. 



+ Contrary to our usual custom, we have copied the symbols of the original text, not 

 from any late conviction of their utility, but lest, by endeavouring to translate them 

 into common language, wc might fall into error. What a sub-arseniiite of a juoto^ide, 

 two-thirds of which consist of deutoxide, may be, we are somewhat puzzled to compre- 

 head.—Ed. 



